I built this set around the Machete+Kapala item combo. There are five levels, each with a somewhat different win condition. The player can never have more than eight HP, so the Kapala will not make them overly powerful.

The set is short to avoid wearing out its welcome, a potential consequence of never boosting the player's abilities.

Neat! Interesting concept to have the player start very powerful instead of building up over time. As you said it might have got old if it were too long, but as i it was quite enjoyable. And I always like seeing original uses for magic signs.